Oscilloscope

An oscilloscope is a test instrument that displays a graph of voltage verses time for one or more signals. The vertical axis is the voltage and the horizontal axis is the time. The two main types of oscilloscopes are digital and analogue.

Digital vs. Analogue

Digital oscilloscopes are becoming a standard among professionals. They are more accurate and precise, and have more features like data storage and network ports. However, this does not include computer software oscilloscopes that use sound cards for input ports. They are only suitable for educational use because of their low accuracy and limited range.

Parts of an Oscilloscope

The front panel has three sections: display, time base, and channels.

• The display is either a cathode ray tube (CRT) or a liquid crystal display (LCD), on which lines are displayed called traces.
• The time base controls the speed of the traces across the screen.
• The channel has a probe input and vertical control for each trace. Basic models have one or two channels, but the professional models usually have four or more.

Using an Oscilloscope

A probe is connected from one of the channel input to the conductor, carrying the signal to be measured. The channel's vertical deflection knob is adjusted until the entire trace is shown on the screen. If the input signal is steady, the time base knob can be adjusted until the trace curve stops moving sideways. The amplitude is calculated by counting the number of grid rows above the line in the center, and multiplying by the vertical control setting. The period is calculated by counting the number of grid columns between two peaks, and multiplying it by the time base control setting. The frequency is the reciprocal of the period.

Uses of an Oscilloscope

Oscilloscope is used to measure analogue waveforms and digital pulses. Problem areas in equipment can be found by comparing the actual trace with the designed trace. Schematics will often have small graphs showing what the trace should look like at certain points in the circuit. They are frequently used as props in movies and television shows.